To download contour line shape files for Austin, go to the Contour Line File Locator Map for the Austin Metro Area.  Note there is also a point file for spot heights.

The following requires that the 3-D Analyst extension be loaded in ArcView. I recommend that you take the 3-D Analyst QuickStart tutorial before using this extension. You can find it in the 3-D Analyst manual, located on the GIS shelves in Sutton Lab.

Before creating a TIN from contour lines, make sure you have clipped the contour lines to the smallest possible area. The TIN creation and analysis puts a huge strain on our computer processing capabilities and the smaller the area the better this will work.

The following information comes from ArcUser magazine's series on terrain modeling. To see the whole series, go to Terrain Modeling Using ArcView GIS (http://www.esri.com/news/arcuser/0799/avmodel.html).

Follow these steps to build a TIN (note that a TIN can be built just from contour lines, or from mutliple sources):

1. Select contour lines as the active theme (if you have a boundary area polygon for the contour lines, or a spot height point file, you can also make these active as well by pressing down the shift key and selecting them in addition to the contour lines)
2. Open the data table and sort the Elevation field (or other field containing the elevation information).
3. Inspect the data to find "outliers" (i.e., data that is too low [typically 0], too high, or blank.) If necessary, exclude improper data by using the Query tool to select all the incorrect records, start editing the theme, and delete these records. Save edited theme and stop editing.
4. Choose Surface - Create TIN from the Surface menu. The TIN function will show whatever themes were active as available  for making the TIN.
5. In the Create New TIN dialog, click on the contour line theme and specify Height Source as the elevation value field, change Input As from Hard Breaklines to Mass Points, and leave the Value field set to  <none>.  If you are also using a boundary polygon, then also click on this theme and specify this will be used as a soft clip polgyon with no height information. If you are using the spot heights, click on this theme, choose Input as Mass Points, and specify height source as the elevation value field.
6. Click OK and specify an appropriate path and filename.

The TIN creation process will take a while.

To see more about how to work with your new TIN, go to Arc User's article on terrain modeling and creating 3-D elevation models. See especially the section on "Draping and Modeling 2-Dimensional data in a Three-Dimensional World" about half-way down the web page.  This has very useful tips for displaying 3-D scenes.

To create a slope grid from the TIN, make the TIN-theme active, choose Surface - Derive Slope (warning: this calculates slope in degrees not percent, and assumes that your elevation and horizontal units are in the same unit, e.g., both feet. To calculate  percent slope and/or if your elevation unit is different than your horizontal unit, e.g., elevation in meters, and xy units in feet, see Creating a slope map from DEM )

To create a aspect grid from the TIN, make the TIN-theme active, choose Surface - Derive Aspect.

To see your new TIN and other data sets in 3-D, first turn off the display TIN in the view, make sure that the TIN-theme is active and choose Edit-Copy Themes. Then go to the Project Menu, and scroll down the icons (View, Tables, etc.) until you come to "3-D Scenes". Double-click on this icon to create a new 3-D scene. In the new 3-D Scene, choose Edit-Paste (from the main menue) to paste the TIN into the view. You can then click on it in the 3D Scene legend to display it.

To drape other themes over the TIN, turn them off in the View and then copy and paste them into the 3-D scene as well.  For each theme, choose Theme - 3-D properties. In the 3-D properties dialog box, choose the button for assigning base heights by surface. This will drape the themes over your TIN surface.

There are many other features you can use, but these are the basics.  Good luck!

Example of a 3-D image created in ArcView by Cesar Escalante - it shows the area around Shoal Creek and Lamar just north of the river.